best directional antenna

When free space is the communication channel, antennas radiate and receiver the signal. Theory shows that the antennas operate effective only when their dimensions are of the order of the magnitude of wavelength of the signal being transmitted...

The length ( l ) and the width ( w ) of a rectangle with an area of 48 m 2 are related by the equation l w = 48. Which of the following best describes the model? => can′t be determined or indirect variation or direct and indirect variation or direct variation..

. A good quality service can be continuously ensured by a global operational satellite system. Thus, communication satellites would give a valuable service in addition to the submarine cable and high frequency radio systems. Geostationary communication satellites have enabled not only national but ..

The best method to demagnetize is by keeping the magnet in a coil through which an alternating current is passed. When the current starts flowing through the coil, the magnet is pulled out of the coil in east-west direction and kept far away. The magnetic field produced du..

The best method of making a powerful magnet is by passing electric current. Wind a length of an insulated copper wire around a steel rod DY and connect it to a battery and a switch. After the current has passed through the coil for some time you will notice that the steel rod gets ma..

Let us now discuss the basic principles of wireless radio communications. We shall mainly concentrate on the principle of amplitude modulation and demodulation. The simplest scheme of wireless communication would be to convert the speech or music to be transmitted to electric signals using a microp..

A few examples of Transmission Lines Transmission lines are everywhere and are of infinite variety but regardless of type, length, or construction, all operate according to the same basic principles. Typical transmission lines include coaxial cable, a two-wire line, a parallel-plate or planar line,..

Variations, the raw materials for evolutionary change, are controlled by genes. When there is an error in DNA copying during sexual reproduction it leads to variation. Variations occur due to microevolution, that is, evolution on a small scale-within a species or a single population. It is defined..

A completely satisfactory theory of magnetism has still not been formulated. At present it is assumed that magnetism is due to the movement of the electrons. The electrons circulate around the nucleus of the atom. They also spin around an axis through their centres. These two movements set up magne..

Oersted's experiment shows that a current carrying wire exerts a force on a magnetic needle and deflects it from its usual north-south position. The reverse must also be true, which was proved by the French scientist Andre Marie Ampere, who suggested that a magnet must also exert an equal and oppo..